Wood bearings

[A.K. Boomer]

I was visiting a friend recently and he had a shelf made from a large plank of wood. Not just any wood, but a piece of wood originally intended to be a commercial helicopter blade. It had a very large number of growth rings per inch. IIRC, it was spruce.

That's a new one to me - had no idea they ever used wooden blades on a chopper.... no offence to the old schoolers on this one but "you go first" i'll video it....

Way different than compact little single engine plane props...

[The Artful Bodger]

The Bell 47, as seen in MASH TV show, had wooden blades. We have one in our museum, in fact we have a small number of choppers but I have not looked at the others.

[A.K. Boomer]

The Bell 47, as seen in MASH TV show, had wooden blades. We have one in our museum, in fact we have a small number of choppers but I have not looked at the others.

That's amazing they not only hold up but withstand the deflection from the pitch at that length --- it's pretty incredible....

[The Artful Bodger]

That's amazing they not only hold up but withstand the deflection from the pitch at that length --- it's pretty incredible....

Helicopter blades operate in a world of complex dynamics, they are not even very strong.

[A.K. Boomer]

Helicopter blades operate in a world of complex dynamics, they are not even very strong.

When you compare them to a massive airplane wing and all it's reinforcement it's amazing they get it done - lifting the craft that is ---- the plane does it indirectly with forward motion but the choppers blades are directly lifting the entire craft,,, so they do have to have some strength in those skinny little things....

[Black Forest]

I have an old cement mixer that uses a wooden gear to turn the barrel. The wooden gear worked against the ring gear. I have since converted it to hydraulic.

[The Artful Bodger]

When you compare them to a massive airplane wing and all it's reinforcement it's amazing they get it done - lifting the craft that is ---- the plane does it indirectly with forward motion but the choppers blades are directly lifting the entire craft,,, so they do have to have some strength in those skinny little things....

Yeabut, the helicopter rotors operate in tension from centrifugal forces in fact if rotor speed is reduced too much in flight the blades will bend/hinge upwards and the pilot will experience a laundry emergency.

[I make chips]

Finally something you can turn on a Harbor Freight lathe without getting chatter ! ! !---Doozer

Cocktail out the nose. Schitt that burns, damn you Doozer

[Bented]

Finally something you can turn on a Harbor Freight lathe without getting chatter ! ! !

---Doozer

The chatter remains, you simply cannot hear it.

[Glug]

The chatter remains, you simply cannot hear it.

If a harbor freight lathe chatters in the woods and Doozer isn't around to hear it, does it make a sound?

[dalee100]

We had a on old Case combine at the farm that had wood bearings on the straw walker cranks.
Wood bearings are still used in hydro turbines around the world.

Yep. My 1166 Case combine had split wood box bearings on the straw walkers. It was a pretty old machine when I bought it at auction and the boxes were pretty well worn. I was unable to source new ones so I rummaged around in the hayloft of my barn and found some dried out draft horse tack, soaked strips of that in gear oil, put that in the journals and went about my merry way. I was told they were made from white oak, but after 20+ years of use, who knows what they were made from.

It got me by for a couple more years before I bought a used 4400 JD to replace it.

[A.K. Boomer]

Yeabut, the helicopter rotors operate in tension from centrifugal forces in fact if rotor speed is reduced too much in flight the blades will bend/hinge upwards and the pilot will experience a laundry emergency.

Absolutely, was thinking about that earlier that it's the tensile strength that helps aid in the ability to provide lift and just like you say if you took it away the blades could actually snap if you tried to support the craft with them in a static mode... still - that's a fair amount of tensile strength to be able to hold together in such an environment of torsional flexing and strange harmonics associated with different RPM's and loading ....

[nickel-city-fab]

Nothing like the strength of Nature, doing its thing one cell at a time with DNA for a blueprint. I have heard of early lathe spindles being bedded in wood bearings, with soap and talc for lube. Think "early 19th century blacksmiths lathe"

[Stepside]

70 years ago when I was ten years old my father ordered new wringer bearings for a washing machine. I replaced them and they were oil impregnated maple My mother ran the machine another 20 years on the bearings. This was doing all the laundry for my father and 5 children.

[The Artful Bodger]

AFAIK, Bell and some Robinson helicopters have 'semi-rigid' teetering rotors while most other manufacturers use semi or fully articulated blades.

There is quite a difference and the subject is I suggest well worth research for enquiring minds.